Medical or active implants are known from the state of the art in great diversity. In the context of the present invention, an electromedical implant shall be understood to mean an implant that comprises a power supply unit (such as, for example, a battery) and electrical and/or electronic components such as, for example, a printed circuit board, which are disposed in a housing that is hermetically sealed. Such electromedical implants are, for example, cardiac pacemakers, defibrillators, neurostimulators, leadless pacemakers, cardioverters, drug pump implants, cochlear implants or other hermetically encapsulated electronic products for implantation in a human or an animal body.
Such implants are frequently connected to electrode lead wires, which after implantation in a human or an animal body treat the same, for example, by transmitting and/or delivering stimulation pulses and/or defibrillator shocks to certain sites of the body, or which are used to detect electrical potential of and from sites of the body. For this purpose, an electrical connection must be established between the electrical and/or electronic components disposed in the housing interior and the respective electrode lead wire. This electrical connection is generally implemented by way of a feedthrough and/or what is known as a header. Such a feedthrough ensures at least one electrical connection between the interior of the housing and the exterior, while also hermetically sealing the housing of the implant. The header, attached via the feedthrough, continues the electrical connection of the feedthrough to a contact point and is used to plug the at least one electrode lead wire into a corresponding, and usually standardized, socket. An electrical contact is thus established between the implant and the connecting piece of the electrode lead wire at the contact points of the bushing. A feedthrough and a header can also be implemented in a single component. In this case as well, such a combined component is generally referred to hereafter as a feedthrough.
Such feedthroughs generally comprise an electrically insulating body, this being the insulator, which is frequently produced from ceramic or other similar material and implements the hermetic sealing of the housing. The insulator often has a flange for this purpose, by way of which the insulator is inserted into the open end of the housing of the implant. The insulator furthermore frequently includes continuous cut-outs, such as, for example, boreholes, in each of which a connection pin (hereinafter abbreviated as pin) is provided, which is also referred to as a terminal pin. The pin is frequently attached in the cut-out, which can additionally comprise a feedthrough sleeve, by way of high-temperature brazing. The pin is used to establish an electrical connection between the housing interior and the header or the electrode lead wire. Such a feedthrough comprising a pin is known from the published prior art European Patent Application No. EP 2 371 418, for example, which shows and describes in particular a feedthrough comprising a terminal pin. The pin comprises a first section made of a biocompatible material and a second section made of a material that can be joined using low energy. The second section is to be disposed in the interior of the housing of the implant.
Brazing is a known thermal process for integrally joining materials, the process being usable to establish an electrical connection and being carried out using a solder. Depending on the temperature, a person skilled in the art distinguishes between three known methods. The process is referred to as soft soldering in the temperature range up to 450° C. Known soft solders are Sn63Pb37, Sn96Ag4 and Au80Sn20, for example. The process is referred to as brazing in the temperature range between 450° C. and 900° C. For this, silver or brass solders are frequently used (such as, for example, L-Ag44 (Ag44Cu30Zn26)). The process is referred to as high-temperature brazing at temperatures above 900° C. In medical technology, high-temperature solders include Au (99.95), AuAg8, AuPt10 and Ti60Ni25Cu15, for example.
Conventionally, the pin disposed in the feedthrough is directly connected to a terminal of a printed circuit board by way of soft soldering or welding so as to establish the electrical connection with the electronic circuit located on the printed circuit board. The published prior art European Application No. EP 2 529 790 discloses the use of a connector, which is attached to the terminal pin by way of a clip connection. The connector moreover comprises a sleeve, which surrounds the terminal pin and is fixed on a printed circuit board disposed in the interior of the implant by way of soft soldering or welding so as to establish an electrical connection.
In the production of such feedthroughs and implants, in particular, inserting and brazing the pin and establishing the electrical connection between the pin and the printed circuit board are complex and cost-intensive. The elements of a pin are initially produced individually and then assembled and joined manually.
For example, gold solder rings or sleeves are produced separately prior to brazing the pin to the feedthrough and are manually assembled individually with a pin. The problem that exists with this process is that the entire feedthrough must be removed if a solder ring or a solder sleeve falls off during mounting. In the case of multi-pole feedthroughs, the costs resulting from mounting errors are therefore very high. Additionally, the problem exists that the product groups encompassing the pin and solder arrive individually in the receiving department of the producing company. Until processing, these product groups must be stored separately from other components. This likewise creates high complexity for each component in materials management. Moreover, each component must be independently tested for defects. The complexities for individual processes that are related to this (stamping, cleaning, sorting, packaging, etc.) exceed the material value of the respective component several fold.
Using an upstream high-temperature brazing process, the solder can be brazed onto the wire pin. However, this is a multi-stage joining process using the individual components, in which overall no savings are achieved in terms of labor time or cost.
Additionally, the option exists to coat the pins with solder material by way of electroplating or by way of coating methods. However, the galvanic coating of wire sections in the form of bulk material is likewise very complex, since a uniform layer thickness can only be assured by previously separating and aligning the pins. Moreover, inclusions from the electroplating solution may occur. Such an electroplating solution additionally often represents a dangerous or toxic substance, which is undesirable in the field of medical technology and may be problematic in terms of disposal.
If PVD or CVD methods are used for coating, the maximally achievable layer thickness is limited to several 10 μm due to economic efficiency. This method likewise necessitates separation of the pins. It may be necessary to mask the pins for the application process, making the method not cost-efficient for the application of a sufficient amount of solder.
The production process is also initially separate on the implant interior at the contact point between the pin and the printed circuit board, which is normally joined by way of a soft solder joint using, for example, SMT methods. The required soft solderability for the SMT process is created by adding further components during or after the high-temperature brazing process.
Overall, bulk material is problematic to process in production since the respective components must be singulated, aligned and optionally oriented prior to processing, which represents an additional process step that is required for measuring or testing tasks in a partially or fully automated production plant.
The present invention is directed toward overcoming one or more of the above-mentioned problems.